In general, an excavator, which is a kind of construction equipment, is an equipment that moves earth (dirt) for excavating earth and sand or rock, and has a structure in which a front part of a car body thereof includes an arm and a bucket for excavating earth and sand or rock is mounted at an end part of the arm.
The bucket is manufactured of a steel sheet having a high hardness value in order to enhance abrasion resistance. However, since a bucket is manufactured with welding technology, there is a limitation in using a steel sheet having a high hardness value. This reason is because carbon or alloy components need to be put in to enhance the hardness, but weldability deteriorates when the content of the components is high. Accordingly, cast steel parts having a high hardness value, such as a tooth, a shroud or a cutter, are mounted and used in order to reduce damage to the bucket using a coupling method instead of welding. However, these parts also have a limitation in life span due to abrasion.
Meanwhile, in order to enhance weldability and abrasion resistance of a tooth coupled to a bucket, a technology in which tungsten carbide having a high hardness is arc welded has been proposed (see KR20-1999-011857). However, since tungsten carbide having large particle sizes is used in the technology, cracks are generated in an excavation in which impact is high or a work in which base rock is broken, so that there is a problem in that weldability and abrasion resistance deteriorate.
Therefore, there is a need for developing cast steel parts showing high strength and having excellent abrasion resistance and durability in order to enhance the life span of the bucket.